Means for regulating the height of fuel mounds within a furnace



.Jan. 17, 1967 J. A. CLARK, sR

MEANS FOR REGULATING THE HEIGHT OF FUEL MOUNDS WITHIN A FURNACE 2 Sheets-Sheet 1 Filed May 6, 1964 Fig./

Jan. 17, 1967 J. A. CLARK, SR 3,298,338

MEANS FOR REGULATING THE HEIGHT OF FUEL MOUNDS WITHIN A FURNACE Filed Ma y e, 1964 2 Sheets-Sheet 2 Fig.3

Joseph Avafia Clark, 5r.

INVENTOR.

United States Patent O 3,298,338 MEANS'FOR REGULATING THE HEIGHT OF FUEL MOUNDS WITHIN A FURNACE Joseph Avatia Clark, Sr., Rte. 1, Box 362, Sweet Home, Oreg- 73666 Filed May 6, 1964, Ser. No. 365,400 7 Claims. (Cl. 110101) This invention comprises a novel and useful thermostatic control for automatic furnace firing and more particularly pertains to a probe or lance adapted to be inserted into a furnace and operable to regulate the feed of fuel into the furnace by the automatic fuel feeding system thereof.

In certain types of furnaces, and especially in industrial furnaces of large capacity including incinerators and the like, fuel is consumed in the combustion chamber of the furnace in one or more mounds, cones or piles adjacent one or more corresponding fuel inlets into the furnace and which are supplied by fuel in an automatic manner. In order to properly regulate a combustion within the furnace it is desirable to sense or determine the rate or extent of combustion at each of the fuel inlets and regulate the feed of fuel thereto accordingly. Moreover, in furnaces using various types of solid fuel such as wood refuse or hog fuel; sugar cane or bagasse, coal and other solid fuels all of which are supplied by an automatic firing system, it is evident that the rate of combustion and the rate of supply for the fuel will necessarily vary.

It is therefore the primary purpose of this invention to provide an automatic thermostatic control adapted for use with automatic firing systems of different types of furnaces handling different types of fuel.

A further object of the invention is to provide an automatic thermostatic control which will provide extremely accurate control over the firing of a furnace and will be especially responsive and sensitive to the rate of combustion in various portions of the furnace combustion chamber.

A further object of the invention is to provide a thermostatic control in accordance with the preceding objects which is readily insertable to selected depths into a furnace combustion chamber into a selected mound of burning fuel therein and shall be operable to very accurately control the automatic feeding of fuel to that mound in the combustion chamber. Since different fuels may, for reasons of efficiency, require fuel mounds of varying heights it is important to provide means readily permitting the vertical positioning of the thermostatic control within the furnace.

Still another object of the invention is to provide a thermostatic control in accordance with the preceding objects which may be readily inserted into the furnace in a variety of manners as convenience may dictate and yet shall effectively perform its combustion sensing operation therein and in response to such sensing operations shall accurately control an automatic feeding system for supplying fuel to the furnace.

A still further object of the invention is to provide an accurate thermostatic control for automatic firing systems of furnaces which shall be well protected against the temperature existing within the furnace.

A further object of the invention is to provide a device in accordance with the foregoing objects which shall be capable of being readily adjusted to different ranges of operating temperatures within a furnace and to different rates of feed of fuels by the automatic feeding system of the furnace.

A more specific object of the invention is to provide a temperature sensing probe adapted to be embedded in a cone or mound of fuel in the furnace combustion cham- 3,298,338 Patented Jan. 17, 1967 ber and which shall include a water or other fluid medium circulating means through the probe cooling the same whereby the medium itself will be heated by the combustion temperature within the furnace together with a thermostatic control element disposed in heat exchange relation with the cooling medium circulated through the probe and which in turn is connected to a furnace automatic heating system for controlling the operation of the latter.

A still further object of the invention is to provide a device in accordance with the foregoing objects and which can be readily installed during the operation of the furnace.

Still another object of the invention is to provide a control device in the form of an elongate probe in accordance with the preceding objects which shall be capable of downward insertion through the roof of the furnace as through the fuel inlet therefor or up into the grates of the furnace into the mound of burning fuel.

And a final important object of the invention to be specifically enumerated herein resides in the provision of a thermostatic control means in accordance with the foregoing objects which will in no manner interfere with or preclude the manual control of the firing system of the furnace or any of the other conventional furnace controlling mechanisms and operations.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a diagrammatic view showing the application of a suitable embodiment of a thermostatic control of this invention to the automatic fuel feeding system of a furnace and with the sensing probe being inserted downwardly through the roof of the furnace and the fuel feed duct therefor into a mound of fuel;

FIGURE 2 is a detail view in vertical section through the sensing element of the probe;

FIGURE 3 is a view in vertical section through a portion of a furnace showing the manner in which a plurality of probes are applied each to a mound of burning fuel; and

FIGURE 4 is a view in vertical section of a modified construction in which the probe is inserted upwardly through the grate of the furnace into the mound of fuel.

' together with a roof structure 14 and a grate 16. 'Indica ted at 1-8 is a pile, cone or mound of burning fuel within the furnace, the feed of fuel to which is to be controlled by the thermostatic control system indicated generally by the numeral 20 in accordance with this invention.

The furnace is shown as being provided with a fuel feed inlet 22 which is supplied by fuel as by fuel inlet duct 24 from any suitable source of supply 26 having a fuel feed control valve 28 associated therewith. In the form illustrated, fuel may be supplied to the source 26 in any suitable manner as by means of a conveyor assembly, a gravity feed or the like. Further, the fuel feed control means 28 may be of any suitable character, that illustrated consisting of a plate providing a sliding valve.

The thermostatic control 20 includes an elongated probe 30 in the form of a hollow rod or shaft whose lower end is provided with an enlarged casing or bulb 32. As shown in FIGURE 2, the bulb 32 is provided with a chamber 34 therein for the reception of a fluid medium and may be provided with a somewhat pointed lower extremity as 3 at 36 to facilitate its penetration into the mound or pile of fuel 18.

At its upper end, the probe 30 is provided with a T- coupling 38 into which is fitted and into which extends a conduit in the form of a pipe 40. The latter is open at its lower end as shown in FIGURE 2 toward the lower portion of the chamber 3- while its upper end is connected as by a supply conduit 42 and an adjusting valve 44 with a source of supply such as a conduit 4-6. A further valve 48 consisting of a manually adjustable pressure regulating valve is interposed in the conduit 46 so that any suitable fluid medium such as water from any suitable source under pressure may be delivered into the conduit 40 at a regnllated pressure and rate of flow. Also connected to the stem of the T-coupling 3% is an outlet or discharge conduit 50 which discharges into a drain or the like as at 52. As so far described, it will be apparent that by properly adjusting the valves 44 and 48, circulation of a medium, water or other medium, may be obtained from the source, through the probe 30 and from thence to the drain 52. The medium Will be heated proportionally by the temperature prevailing within the combustion chamber with consequent heat transfer to the medium resulting in the protection of the probe 30 from the ravages of the temperature within the firebox or combustion chamber 12.

Indicated generally by the numeral 60 is a thermostatic actuator which is shown connected by a coupling 62 to the discharge line 50 so that the thermostatic actuator 69 is in good heat conducting relation with respect to the circulated fluid medium passing through the probe after the medium has been heated by combustion chamber temperature. Conveniently, the actuator 60 may consist of a thermostatic switch, although any other thermally responsive element may be suitable for this purpose. When the thermostatic actuator consists of a switch, it is supplied with electrical current from any suitable source as by means of the connector 64 which in turn is connected to a source of power as by the conductor system indicated at 66.

As will be further noted from FIGURE 1 the pressure responsive means in the form of a cylinder piston unit 68 has its piston rod '70 connected to the valve 28 for actuating the latter between an open and closed position and to varying positions between fully open and fully closed positions. A source of fluid under pressure (not shown) is supplied by the delivery conduit 72 to a selectively operated control valve '74 and the conduits 7'6 and 78 communicating with the cylinder and piston unit at the ends of the latter.

An adjustable clamp indicated at 80 is slidable within a vertical slot (not shown) along the wall of the fuel inlet 22 to permit vertical positioning of the probe 30 and specifically the enlarged casing or bulb 32 thereof relative to the fuel mound 18.

From the foregoing, the operation will now be readily apparent. As the temperature within the combustion chamber varies, it will be detected by the circulating fluid medium in the probe and in turn will correspondingly control or affect the thermostatic control actuator 69. The latter with its electric circuit 66 correspondingly adjusts the control valve 74- and thus operates the fluid pressure actuator 68 to thereby correspondingly open or close the valve 28 to the desired extent. Thus, the supply of fuel will be controlled in accordance with the combustion chamber temperature 60 at the particular mound 18 with which the device is associated.

In the form illustrated, the probe is shown as extending through openings in the feed duct 24 and through the feed inlet 22 into the furnace, any conventional type of adjustable clamp 80 being provided to regulate the penetration of the probe into the mound 18.

It is evident that by appropriate adjustment of the sensitivity of the thermostatic actuator as by a control knob 82 thereon, the range of operating temperature of the device can be varied. Thus, a very sensitive control may be provided for delivery of the fuel to the particular mound of the furnace with which the device is associated.

As shown in FIGURE 3, a plurality of such probes 30 may be provided, each being associated with one of the piles or mounds 18 of burning fuel within the combustion chamber. As further shown in FIGURE 4, the probe 3d may be inserted into the combustion chamber upwardly through the grate 16 into a mound 18 from the lower side thereof. This arrangement has the advantage that the probe is even 'better protected from the heat of'the combustion chamber by being embedded entirely within the mound.

It is to be understood that it is within the scope of this invention to employ various types of mechanisms for operating the fuel feed control valve 28 in lieu of the fluid pressure actuator 68. Further, various types of thermostatic actuators may be employed as the actuator 6% which may be of the type operable in conjunction with variable control means to regulate according to furnace temperature the positioning of valve 28 to intermediate positions.

In a preferred form of the invention, the point 36 is removably threadedly engaged in the lower end of the bulb 32. This enables easy access to the bulb 32 for servicing or the like. In addition, the point 36 is of a soft, fusible material so that in the event of a water failure it will melt or blow out by a steam pressure buildup in the bulb. This is a safety feature in the device.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is a follows:

1. A thermostatic control for an automatic furnace firing system comprising a probe adapted for insertion into the combination chamber of a furnace and for penetration of a mound of burning fuel therein adjacent a fuel feed inlet,

means for circulating a fluid medium through said probe thereby cooling the latter and heating said medium,

a thermostatic actuator in heat exchange relation with the heated medium,

means regulated by said thermostatic actuator controlling the feeding of fuel into said furnace through said fuel feed inlet, said probe comprising an elongated tube having a sensing element at one end, a pipe within said tube having an end opening into said sensing element,

means supplying a fluid medium into the other end of said pipe,

means for discharging said heated fluid medium from said tube and conducting it to said theromstatic actuator, and

said sensing element comprising a bulb having a removable heat fusible closure element in its lower. end.

2. A thermostatic control for an automatic furnace firing system comprising a probe adapted for insertion into the combustion chamber of a furnace and for penetration into a mound of burning fuel therein adjacent a fuel feed inlet,

means for circulating a fluid medium through said probe thereby cooling the latter and heating said medium,

a thermostatic actuator in heat exchange relation with the heated medium,

means regulated by said thermostatic actuator controlling the feeding of fuel into said furnace through said fuel feed inlet,

said probe comprising an elongated tube having a sensing element at one end, a pipe Within said tube having an openinginto said sensing element, and

said sensing element comprising a bulb having a removable heat fusible closure element in its lower end.

3. A thermostatic control for an automatic furnace firing system comprising,

a probe adapted for axial insertion into the combustion chamber of a furnace and for penetration of a mound of burning fuel therein subjacent a fuel feed inlet,

means for circulating a fluid medium through said probe thereby cooling the latter and heating said medium,

a thermostatic switch in heat exchange relation with the heated medium,

fuel feed control means regulated by said thermostatic switch controlling the feeding of fuel into said fuel feed inlet,

said probe further comprising an elongated tube having a substantially pointed sensing element at one end facilitating its insertion into a mound of fuel, and

adjustable clamping means associated with said probe for selectively positioning said sensing element carried thereby to desired depths within the furnace.

4. The combination of claim 3 wherein said fuel feed control means includes a fluid control valve and a pressure responsive cylinder in communication with said fluid control valve and coupled with a plate for powered movement of the plate while bearing the weight of an imposed load of solid fuel.

5. The combination of claim 3 wherein said thermostatic switch includes adjustment means for selectively determining the operating temperature of said switch.

6. The combination of claim 3 wherein said thermostatic switch and said fluid control valve are in circuit with a source of electrical power.

7. The combination of claim 1 wherein means supplying a fluid medium includes a pressure regulating valve.

References Cited by the Examiner UNITED STATES PATENTS 1,208,585 12/1916 Lazzell -118 X 1,358,072 11/ 1920 Fulton 263-1 1,506,758 9/ 1924 Little 236-15 X 1,521,669 1/ 1925 Bosselmann.

1,763,666 6/1930 Machlet 236-82 2,047,579 7/ 1936 Cross 236-15 2,366,236 1/194-5 Clark.

ALDEN D. STEWART, Primary Examiner. 

1. A THERMOSTATIC CONTROL FOR AN AUTOMATIC FURNACE FIRING SYSTEM COMPRISING A PROBE ADAPTED FOR INSERTION INTO THE COMBINATION CHAMBER OF A FURNACE AND FOR PENETRATION OF A MOUND OF BURNING FUEL THEREIN ADJACENT A FUEL FEED INLET, MEANS FOR CIRCULATING A FLUID MEDIUM THROUGH SAID PROBE THEREBY COOLING THE LATTER AND HEARING SAID MEDIUM, A THERMOSTATIC ACTUATOR IN HEAT EXCHANGE RELATION WITH THE HEATED MEDIUM, MEANS REGULATED BY SAID THERMOSTATIC ACTUATOR CONTROLLING THE FEEDING OF FUEL INTO SAID FURNACE THROUGH SAID FUEL FEED INLET, SAID PROBE COMPRISING AN ELONGATED TUBE HAVING A SENSING ELEMENT AT ONE END, A PIPE WITHIN SAID TUBE HAVING AN END OPENING INTO SAID SENSING ELEMENT, MEANS SUPPLYING A FLUID MEDIUM INTO THE OTHER END OF SAID PIPE, MEANS FOR DISCHARGING SAID HEATED FLUID MEDIUM FROM SAID TUBE AND CONDUCTING IT TO SAID THERMOSTATIC ACTUATOR, AND SAID SENSING ELEMENT COMPRISING A BULB HAVING A REMOVABLE HEAT FUSIBLE CLOSURE ELEMENT IN ITS LOWER END. 